Electric translating apparatus



May 2, 1944. c; H. CHAPMAN 2,348,055

ELECTRIC TRANSLATING APPARATUS Filed Dec. 29, 1942 Fig. I /5 /7 l4 Inventor: Charlesfichapman,

7 His Attorney.

Patented May 2, 1944 UNITED My invention relates to electric translating apparatus, and more particularly to energizing coils for electric induction apparatus, electric relays, and the like. The invention is useful for varying the efiective flux of an electric coil of given size and shape Without changing either the number of turns or the magnitude of the current flowing through the coil. Conversely, the invention may be used to control the number of ampere turns required to obtain fromacoil.

characteristically an electric relay of any particular structure requires flux in the core to effect actuation of the relay.

Since the relay structure the coil size, the required mines the necessary ampere turn rating of the coil. Commonly such relays are supplied in different current ratings by providing the relay with size and shape but which differ inversely in their current rating and number of turns, so that the ampere turn ratings of all mately the same. This method of increasing the current rating of a relay has definite limitations. '35 tact structure of the relay is n t nec ssary here, but in principle the relay comprises a transformer having a short circuited secondary winding and a thermal responsive member positioned in thermal transfer relation to the secondary winding. coils which differ by only one turn is necessarily an o e sp y, e T619437 p es a mag etizable iron core it slotted or otherwise cut away longitudinally at M to receive a thermally deformable bimetallic strip i2. rounded by a cylindrical copper conductor i3 which serves as a short circuited secondary winding arranged in transformer relation with respect to an energizing or primary winding it.

Referring now more particularly to the enlarged sectional views of Figs. 2 and 3, it may be Accordingly t is a general bject of my i m noted that the relay energizing coil which I have shown in connection with the relay of Fig. 1 cornprises the current conducting winding l4 and a supporting coil spool l5 formed of suitable insulating material. In accordance with my in- It is a further object of my invention to provide vention, I p ovide a mag et S u for diverting a portion of the flux established by the Winding I i from the relay core ill. netic shunt is built integrally int-o the coil upon the spool i5 and adjacent the inner turns of the the same flux as a similar coil not embodying my winding Hi. It is in. the form of a lamina l6 of magnetizable material. nearly encircling the spool l5 at the base of the winding it and separated from the winding by an overlying lamina ll of suitable insulating material. the magnetic shunt it is substantially cylindrical When the current rating becomes so high that the number of turns in the coils is very small, for example, two or three turns, it will be evident that the steps between the current ratings of large. For example, the current rating of a two turn coil is per cent of the current rating of a three-turn coil with the same ampere turn rating. While it is frequently desirable to provide coils having current ratings between these widely 3 differing values, it has been found that in coils of the type described it is impossible to obtain any intermediate effect from a fractional part of a turn on the coil.

vention to provide means for varying the current rating of electric coils of predetermined size and shape while maintaining a predetermined fixed number of turns on the coil.

means for reducing the effective or core flux established by an electric coil without changing the current or the number of turns in the coil,

so that a greater current invention.

It is a specific object of vide a magnetic shunt built integrally with an electric energizing coil for the coil flux from the centrally located core of STATES ELECTRIC TRANSLATING APPARATUS Application December 29, 1942, Serial No. 470,491

9 Claims. (Cl. 356) a definite amount of ordinarily determines actuating flux deterthe coils are approxi is required to supply the invention to proshunting a portion of arss'r OFFICE the coil, thereby to control the current rating of the coil for any predetermined core flux without changing the number of turns.

My invention itself together with further objects and advantages thereof will be more fully understood by referring now to the following detailed specification taken in conjunction with the accompanying drawing in which Fig. 1 is a sectional View of an electric relay embodying my a predetermined flux 10 invention; Figs. 2 and 3 are enlarged sectional views of the energizing coil shown on the relay of Fig. 1; and Fig. 4 is a sectional View of a coil for a relay or other translating apparatus embodying my invention in modified form.

Referring now to the drawing, and particularly to Fig. 1, I have shown by way of illustration the application of my invention to a thermal overload relay of the induction type. improved energizing winding, which embodies the any one of a number of coils of the same general 20 f s O y tion, the st u t e of the relay of Fig. 1 is described in detail and claimed in Patent 2,051,380 issued on August 18, 1936, to B. W. Jones. In View of the foregoing patent a detailed description of the core, frame and con- Apart from the The core I9 is sun As shown, this mag- As shown at Fig. 3,

but is provided with a longitudinal gap l8 so that the shunt nowhere forms a closed metallic path around the core Ill. The gap I8 thus prevents the flow of circulating currents which would otherwise flow in the shunt if the shunt formed a complete short-circuited turn about the core.

While I have shown at Fig. 3 a shunt I6 formed of substantially one complete turn of magnetizable sheet material on the spool l5, it will be clear that the reluctance of the shunt l6 may be controlled as desired by providing either more or less than one complete turn as required. For example, at Fig. 4, I have shown another embodiment of my invention in which the magnetic shunt Iiia comprises a plurality of turns of thin magnetizable sheet material interwound with a lamina 11a of suitable insulating material. It will be noted that by interwinding the shunt Ifia with the insulating material Ila, no complete short circuited current path is provided through the shunt.

The two embodiments of the invention described above are similar insofar as the shunt is positioned upon the core l at the base of the winding I4. It will, however, be understood by those skilled in the art that my invention is not limited, in its broader aspects, to this particular arrangement. The principle of the invention lends itself equally well to the interposition of the magnetic shunt between any desired layer of turns of the winding l4 so long as the shunt I5 is positioned in the region of the inner turns of the winding.

By way of example to illustrate the effective-- ness of the invention, it is interesting to note that in a typical device I have found that a single turn of steel 19 mils thick wrapped upon a given relay coil in the manner illustrated in Fig. 3 resulted in increasing the ampere turns required for tripping the relay by approximately 25 per cent. 'The same coil with two complete turns of a similar steel shunt wrapped in the manner of Fig. 4 was found to require an increase of approximately '71 per cent in the ampere turns necessary for tripping the relay. From these figures it will be evident that by suitably proportioning the cross sectional size of the shunt the desired variations of coil rating, as pointed out in the first part of this specification, may easily be attained.

It is to be noted that the relay illustrated at Fig. 1 does not provide a closed flux path of magnetizable material between the relay core and frame. In certain types of relays and other translating apparatus where such a closed iron flux path is provided, the reluctance of the nor-- mal flux path through the core may be so low that the open flux path through the shunt of my invention to be effective must be a rather large cross section. Thus, while an efiective shunting effect is obtained with such an arrangement, it will be understood that my invention has its greatest application to electric apparatus in which the flux path through the core of the coil is marked by non-magnetic sections of substantial reluctance.

While I have illustrated only certain preferred embodiments of my invention by way of illustration, many further modifications will undoubtedly occur to those skilled in the art, and I therefore wish to have it understood that I intend in the appended claims to cover all such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electromagnetic relay comprising a magnetizable core, means energized in accordance with the magnetic flux traversing said core, an energizing coil mounted upon said core including a current conducting winding and supporting means therefor, and a circumferentially discontinuous magnetizable member integral with said coil and extending longitudinally of said core adjacent the inner turns of said winding and for substantially the full length of said coil, thereby to shunt a portion of the magnetic flux of said winding from said core.

2. An electromagnetic relay comprising a magnetizable core, means energized in accordance with the magnetic flux traversing said core, an energizing coil surrounding said core comprising a supporting spool and a current conducting winding carried thereby, and a magnetic shunt for said core mounted upon said spool adjacent the inner turns of said winding as an integral part of said coil, said shunt extending longitudinally of said core for substantially the full length of said coil.

An electromagnetic relay comprising a magnetizable core, means energized in accordance with the magnetic flux traversing said core, an energizing coil surrounding said core comprising a supporting spool and a current conducting winding carried thereby, and a magnetizable lamina Wound upon said spool integrally with said ccil adjacent the inner turns of said winding to shunt a portion of the magnetic flux of said winding from said core.

4. An electromagnetic relay comprising a magnetizable core, means energized in accordance with the magnetic flux traversing said core, an energizing coil surrounding said core comprising a supporting spool and a current conducting winding carried thereby, and a circumferentially discontinuous layer of magnetizable material interposed between the core of said spool and the base of said winding to shunt a portion of the magnetic flux of said winding from said core, said layer extending longitudinally of said core for substantially the full length of said coil.

5. An electromagnetic relay comprising a magnetizable core, means energized in accordance with the magnetic flux traversing said core, an energizing coil surrounding said core comprising a supporting spool and a current conducting winding carried thereby, and a lamina of magnetizable material interwound upon said spool with a sheet of insulating material at the base of said winding, said lamina forming a plurality of turns about said core.

6. An electric translating apparatus comprising a magnetizable core, means energized in accordance with the magnetic flux traversing said core, an energizing coil mounted upon said core for establishing said magnetic flux in said core, said coil comprising a multiturn current conducting winding, and magnetizable means extending longitudinally of said core for substantially the full length of said coil and wound integrally with said coil adjacent the inner turns of said winding to shunt a portion of the magnetic flux of said coil from said core.

'7. An electric induction apparatus comprising a magnetizable core, a secondary winding surrounding said core for generating an electrometive force proportional to the rate of change of magnetic flux in said core, an energizing coil surrounding said secondary winding for establishing said magnetic flux in said core, and magnetizable means extending longitudinally of said core for substantially the full length of said coil and wound integrally with the turns of said coil to shunt a portion of the flux of said coil from said core.

3. An electric induction apparatus comprising a magnetizable core, a short circuited annulus of electrically conducting material surrounding said core, an energizing coil comprising a spool of insulating material surrounding said annulus and a multiturn current conducting winding wound upon said spool, and a lamina of magnetizable material interwound upon said spool with a lamina of insulating material adjacent the inner turns of said winding thereby to shunt from said core a portion of the magnetic flux established by said coil.

9. An electric induction relay comprising a magnetizable core having a slot extending longitudinally thereof, a thermal responsive actuating member disposed in said slot, a short circuited annulus of electric conducting material surrounding said core and said thermal responsive member, an energizing coil surrounding said short circuited annulus and comprising a spool of insulating material and a multiturn current conducting winding upon said spool, and a magnetic shunt for said core comprising a lamina of magnetizable material interwound with a lamina of insulating material upon said spool and at the base or" said winding, thereby to shunt from said core a portion of the magnetic flux established by said coil.

CHARLES H. CHAPMAN. 

